A conventional article of athletic footwear includes two primary elements, an upper and a sole structure. The upper provides a covering for the foot that securely receives and positions the foot with respect to the sole structure. In addition, the upper may have a configuration that protects the foot and provides ventilation, thereby cooling the foot and removing perspiration. The sole structure is secured to a lower portion of the upper and is generally positioned between the foot and the ground. In addition to attenuating ground reaction forces (i.e., imparting cushioning), the sole structure may provide traction and control foot motions, such as pronation. Accordingly, the upper and the sole structure operate cooperatively to provide a comfortable structure that is suited for a variety of ambulatory activities, such as walking and running, and sports such as tennis, basketball, and skating.
The sole structure of athletic footwear generally exhibits a layered configuration that may include a comfort-enhancing insole, a resilient midsole formed from a polymer foam material, and a ground-contacting outsole that provides both abrasion-resistance and traction.
It is desirable to have outsoles that offer high energy return to the athlete. For example, 1,4-polybutadiene is a known polymer for incorporating into outsoles of athletic and other footwear. However, when combined with other polymers/rubbers, the high energy return is often diminished. Moreover, the bottom contact surface of the polymer can wear out quickly on high impact footwear such as for tennis and basketball footwear. Tennis is often played on an abrasive surface, which increases the wear on the shoe, in particular certain regions of the shoe.
It would be desirable to provide a footwear outsole system that reduces or overcomes some or all of the difficulties inherent in prior known devices. Particular objects and advantages will be apparent to those skilled in the art, that is, those who are knowledgeable or experienced in this field of technology, in view of the following disclosure of the invention and detailed description of certain embodiments.